LeCroy Wavestation 2052 input lag from LabView

[Howdie]

Hi All,

We are trying to use the LeCroy Wavestation 2052 to set up a 2 channel frequency sweep for a new Mass Spectrometer. I have looked through the manual and SCPI commands for this model and formatted some VIs to configure the basic wave parameters for each channel, then put both channels into sweep mode with an external trigger. The problem is that once the commands are sent it takes up to 2-3 seconds for all of the settings to change. In that time the external trigger has already been sent, causing channel 1 to start the sweep before channel 2 is configured. The Wavestation is currently set to USBMTC (I also have the option for USBRAW).

I am currently using LabView version 15.0 with the VISA drivers. Everything is connected and working, but the settings are changing too slow for it to be effective. Eventually the scan times we will be performing will be in the low millisecond range, so I'd like to figure out how to configure the VISA commands to not have this delay. I relatively new to Labview so forgive me if there's some glaring ovbious setting I have overlooked.

Attached are the VI's I have been using to configure and write the wave parameters. I would greatly appreciate any help!

[yea_likethecity]

Howdy Howdie,

We do have some prewritten drivers for the Wavestation 2052 on IDNet, it may be worthwhile to see if they work as well or better than what you've written. These are not supported by National Instruments but they will give us another data point and may suffice for your needs.

LeCroy WaveStation 2052

http://sine.ni.com/apps/utf8/niid_web_display.download_page?p_id_guid=D9E08422CD2449F9E0440021287E6A...

Also, please perform an I/O Trace when you send the command. This will let us know whether the issue lies with LabVIEW sending the command late or your device processing it slowly.

Performing a Good NI I/O Trace Capture for Debugging/Troubleshooting

http://digital.ni.com/public.nsf/allkb/282C5D41E2BA04F2862574BA007803B9

[Howdie]

Austin,

I had already tried the drivers that were provided on IDNet. There were problems with the code (the scan from string in the Read waveform attributes was not formatted correctly, and a few writing examples had spaces in the wrong place). Even after editing the string commands to make the commands run, I was still getting an input delay. Attached is the IO trace for the Test Scan UI.vi. I am in correspondence with a representative from LeCroy, and when they ran the code they too had the delay so I'm starting to think it is a limitation of the device and not the software.

The only two things I haven't tried are using USBRAW (not sure what it does, but when I switch to that mode my computer stops recognizing the device) and trying to use overlapping commands with SCPI. I haven't been able to find much about overlapping commands. I know you need to use *OPC and *OPC? and some other SCPI commands, but can't find a good tutorial resource.

Thanks so much for the help,

Casey

[yea_likethecity]

Casey,

It looks like all your commands are being delivered in the space of a second so I'm inclined to believe it may be an issue with the hardware. USB-RAW is an alternative form of USB communication, so I doubt it would offer much in terms of improved performance. I can't speak for the instrument but my understanding is that some lag is expected with instrument control applications so I would be unsurprised if the behavior you're seeing is just a characteristic of the equipment. Let us know if the representatives from LeCroy have any additional information.